The present invention relates to the field of information handling and processing. More specifically, in one embodiment, the present invention provides for improved processing of information embodied in documents transferred over a network such as the Internet.
The term "Internet" refers to a global internetwork of networks which has gained wide usage in recent times. Communication between any two computers (nodes) can occur on the Internet so long as both computers are connected somewhere to the Internet. The most common protocol for data communications over the Internet is TCP/IP (Transport Control Protocol/Internet Protocol). In a layer above TCP/IP, a number of different transport applications are known. FTP (File Transfer Protocol) is a protocol used to move files from one machine to another. Because of it use, the typical FTP client has an interface similar to a file manager, displaying lists of files and allowing for navigation through directory structures, etc. SMTP (Simple Mail Transfer Protocol) is a protocol used to move e-mail messages between host machines on their way to their eventual destination, usually without user interaction. HTTP (HyperText Transfer Protocol) is a protocol used to transfer documents between nodes where most documents are World Wide Web ("WWW" or "Web") documents (i.e., documents with links to other documents). Typically, HTTP is used between a Web server and a Web browser client. Documents transferred using HTTP might be made up of several components, such as graphic elements and forms, and might include references to other documents. Because a Web browser can display documents for viewing (text, graphics, or video documents) or listening (audio documents) by an end user and can jump from one referenced document to another, an end user perceives that the documents provided using HTTP form a web of documents, hence the term World Wide Web ("WWW" or "Web") used to refer to the collection of linked documents controlled by thousands of entities available over the Internet using HTTP.
Fundamentally, HTTP is a document transport protocol. In current HTTP systems, an HTTP client (usually, but not necessarily, a browser) sends an HTTP request for a document to an HTTP server, which returns the document (if the client has permission to read the document). If the document is a compound document, the HTTP client will read the returned document to find references to embedded documents (typically graphic images) and send out HTTP requests for those embedded documents. When enough data is received to form a document image, the Web browser displays an image of the document. The increasing popularity of the Web is due in part to the fact that a user need only request a document in order to look at it. By contrast, with FTP, the user would have to select a file from a list of files, transfer that file, open the file to determine if any embedded files are needed, select those files from a list, download them, and then finally construct a view of the document.
In some applications, more is required than simply transferring pre-existing documents. Instead of a fixed document, a user might want to receive a document which is dynamically generated when a request for the document is received. One mechanism for creating dynamic documents is the use of Common Gateway Interface (CGI) scripts. With CGI scripts, a client sends a server a document request for a document in the form of a URL (Uniform Resource Locator) where the URL refers not to a document on the server but to a program on the server. The server generates a document in accordance with the program and returns that document to the browser. The server identifies the request as a request to execute a script rather than a request for a document and the server executes the CGI script, possibly using arguments passed as part of the URL. Most browsers make no distinction between a URL for an existing document and a URL for a dynamically generated document. This allows a client browser which is set up only to request and receive documents to display the results of server-side code execution. CGI scripts are used to interface a browser to a database engine on the server side, with search requests being sent to the server as URLs and the search results being returned as a document. Because they are executed at the server-side and the browser makes no distinction, the user cannot control how and when CGI scripts are used.
The user has more control over execution of programs if the computing is transferred with a document, as with the Java language specified by Sun Microsystems, Inc., of Mountain View, Calif. used for writing client-side code (applets). With client-side code execution, the client requests a document and the returned document contains program code imbedded in the document. The client browser, which must be aware of client-side code, executes the code upon receipt. Client-side code execution finds its greatest use performing simple tasks, such as animating graphic elements of a document, which would otherwise require large amounts of bandwidth to execute on the server and transfer over the link between the server and the client.
Java scripts and CGI scripts differ in their locus of execution, but not much else. They are still server-controlled programs because the server operator specifies which Java scripts will be attached to a document. Because both of these methods are server operator specified, they limit flexibility for the user. Server-side code execution cannot be used at the discretion of the reader, since it is set and controlled by the developer of the server Web site. Client-side code execution is limited to documents in which a server has included applets and is limited to use with applet-aware browsers.
Several approaches to providing user flexibility and control have been tried. One approach is to provide specialized client agents. Client agents execute on the same machine as the browser client, to do such things as gather stock quotes, play sound recordings and perform searches. Client agents can be used with the browser client if the browser is aware of the client. For example, a Real Audio.TM. audio player is a simple client agent which can route audio files encountered by a Netscape.TM. Web browser to a computer's speakers because the Web browser has hooks to the audio player. For Web browsers which are not aware of the audio player, the result is that the browser cannot understand what to do with an audio file it receives. Client agents are also limited in what they can do by the bandwidth connecting the client to the network.
Roaming agents are more flexible than client-side or server-side agents, but are not likely to see widespread use. A roaming agent is a program which performs a task specified by the owner of the agent, where the locus of execution changes depending on what the agent finds during execution. While a network with sufficient computing power at each node now exists, roaming agents are still impractical, but for a different reason. With the growth and commercialization of the Internet, security is a problem and resources can be easily overloaded. Consequently, very few server operators would permit the execution of roaming agents on their systems. For the near future, the only agents which will be allowed to run on servers are agents specifically selected by the server operator. Otherwise, servers would be quickly swamped by users seeking a locus for their agents, or even companies running agents on their competitors' servers to "steal" computing power.
The underlying problem of these various agent systems is that the average user has no suitable place to execute generalized agents, as users are limited to server-side agents provided at the discretion of the server operator or client-side agents which only interact with clients which are aware of the agents and which are often controlled by the server operator.
Specialized systems for information organization have been proposed which can process user information at a locus other than the server or the client, but these information systems require all servers and clients to be aware of the information system. WWWinda, Prospero and TckWWW Robot are examples of such information systems.
What is needed is a computing system which operates preferably in a document-oriented framework such as the World Wide Web, which allows for general agent execution at a locus specified by the user independently of the server or client which might be used.